When using NFS datastores on some NetApp NFS filer models on an ESXi/ESX host, you experience these symptoms:
* The NFS datastores appear to be unavailable (grayed out) in vCenter Server, or when accessed through the vSphere Client
* The NFS shares reappear after few minutes
* Virtual machines located on the NFS datastore are in a hung/paused state when the NFS datastore is unavailable
* This issue is most often seen after a host upgrade to ESXi 5.x or the addition of an ESXi 5.x host to the environment but can also occur in vSphere 6 environment.